BINDING OF AN ESCHERICHIA-COLI DOUBLE-STRANDED DNA VIRUS PRD1 TO A RECEPTOR CODED BY AN INCP-TYPE PLASMID

IncP plasmid RP1 Tra regions are needed to assemble the receptor for l ipid-containing double-stranded DNA bacteriophage PRD1 on the cell sur face. Using radioactively labeled phage and electron microscopic techn iques, we showed that the surfaces of Salmonella typhimurium(RP1) and Escherichia coli(R-P1) cells contained approximately 50 and 20 PRD1 bi nding sites, respectively. Expression of the receptor was growth phase dependent and was highest at late logarithmic or early stationary pha se. The PRD1-resistant RP1 transposon mutants isolated were all Tra-, and the transposons were located in both the Tra1 and Tra2 regions.